The present invention relates generally to a device and method for surgically performing an anastomosis on a hollow organ and more particularly to a device and method for performing an anastomosis on a blood vessel and even more particularly for performing an end to side type of anastomosis, such as a coronary artery bypass wherein the end of a graft vessel is attached to the side wall of a target vessel, such as the aorta or coronary artery of a patient.
Anastomosis is the surgical joining of hollow biological tissues to create an internal communication between them. Vascular surgery often involves creating an anastomosis between blood vessels or between a blood vessel and a vascular graft to create or restore blood flow to essential tissues. Coronary artery bypass graft surgery is a surgical procedure to restore blood flow to ischemic heart muscle whose blood supply has been compromised by occlusion or stenosis of one or more coronary arteries. One method for performing bypass surgery involves harvesting a saphenous vein or other venous or arterial conduit from elsewhere in the body of a patient, or using an artificial conduit, such as one made from DACRON or DACRON and Goretex, tubing, and connecting the conduit from a viable artery, such as the aorta, to the coronary artery downstream of the blockage or narrowing. A graft with both the proximal and distal end portions detached is known as a free graft. A second method of bypass surgery involves rerouting an end portion of a less essential artery, such as the internal mammary artery, from its native location in the chest of the patient to attach the end portion to a coronary artery downstream of the obstruction. This type of graft is known as a pedicled graft.
In the free graft, both ends of the graft are attached to the desired arteries by end to side anastomotic procedures. In the pedicled graft, the distal end portion of the graft is attached to the artery using an end to side anastomosis. As described below, the anastomosis on a free graft includes a proximal anastomosis and a distal anastomosis. The proximal anastomosis involves the attachment of the proximal end of the conduit to the source of blood flow. The distal anastomosis involves the attachment of the distal end portion of the conduit to the destination of the blood flow so as to bypass the obstruction or occlusion. Typically, the proximal anastomosis will involve the attachment of the proximal end portion of the graft to the aorta of the patient and the distal end portion of the conduit will be attached to the coronary artery at a location below the obstruction or occlusion. Preferably, each of these connections will also be end to side connections. Therefore, as described herein, a pedicled graft will involve a distal anastomosis. The anastomosis may also be referred to as a first or second anastomosis. This reference is irrespective of the end portion of the conduit being used and merely refers to the order in which the anastomotic procedure is performed.
At present, the majority of all vascular anastomotic procedures are performed by conventional hand suturing. Suturing an anastomosis is time consuming and difficult. It is important that each anastomosis provide a smooth and open blood flow path for the blood and the attachment must be leak free under relatively high pressures. A completely leak free anastomosis is not always achieved on the first try. Consequently, there is a frequent need to re-suture the anastomosis to close any leaks or remove any flow interruptions that are detected.
The time consuming nature of hand sutured anastomotic procedures is of special concern in bypass surgery because many procedures are performed while the patient is on cardiopulmonary bypass. During this type of procedure, the heart is isolated from the systemic circulation and the heart is stopped from beating. Recent studies have indicated that the rate of post surgical complications may relate to the length of time a patient is on cardiopulmonary bypass. Therefore, an increasing number of surgeons are performing the bypass procedure on patients while the heart is beating. In these procedures, it is important to maintain the heart tissue adjacent to the blood vessel motionless so that the anastomosis may be performed in a timely manner without leaks or interruptions in the flow of blood through the anastomosis. Performing an anastomosis on a beating heart presents a unique challenge to the surgeon because the tissue surrounding the anastomotic site continues to move in a three dimensional manner while the surgeon is attempting to precisely place the sutures for the procedure.
In order to reduce complications relating to the performance of the anastomosis, various stapling devices have been proposed in an effort to provide a consistent and rapid anastomosis. One such device is proposed in U.S. Pat. No. 5,817,113 granted to Gifford et al. In this patent, a stapling device having a staple with an anchoring portion and a coupling portion is proposed to secure an everted portion of the conduit to the target blood vessel. Additionally, a flange member is used to secure the graft to the target vessel in combination with the staple member. Another approach is illustrated in U.S. Pat. No. 5,676,670 granted to Kim. In this patent, a stent-like device is proposed to extend outwardly from the opening in the target vessel to provide a surface for attachment of the conduit thereto. In this procedure, the stent-like member is inserted into the target vessel from the outside surface and then the distal end portion of the stent-like member is disclosed as being expandable to engage the interior surface of the target vessel. U.S. Pat. No. 5,972,017 granted to Berg et al. also discloses the use of a stent-like member or conduit that is attached to the inside of the target vessel and extends outwardly therefrom for the attachment of the graft thereto. U.S. Pat. No. 5,607,444 granted to Lam illustrates a stent-like member that includes a body portion and a deformable flaring portion. The body portion is adapted to fit within the side branch of a blood vessel and the deformable flaring portion is adapted to fit within a bifurcation of a blood vessel to repair a diseased blood vessel at the bifurcated area.
It is submitted that a need remains for a device to perform an anastomosis in L timely and reliable manner. In particular, it is desirable for a method and device that allows the surgeon to perform multiple bypass procedures using various grafts in a less invasive manner, if desired, and in a manner which allows the surgeon to perform the distal and proximal anastomosis using a procedure that reduces the risks to the patient.
The coronary arteries are typically about 1-2 mm in diameter, and the pumping heart can move these arteries over distances of several millimeters during each heartbeat. Because the movement of even 1 or 2 millimeters can result in a displacement of the grafting site that can substantially interfere with forming an effective anastomosis, it is desirable to restrain movement of the artery at the surgical site in any direction to less than 1 mm and provide a simple and quick way to secure the graft to the target vessel and bypassed artery. The potential for difficulties from inadvertent movement is further minimized with the present invention by piercing the target vessel from the interior.
An advantage of the present invention is that either the proximal or distal anastomosis may be performed first depending on the preference of the surgeon and multiple procedures may be performed.
A further advantage of the present invention is that the need for a xe2x80x9cside bitingxe2x80x9d clamp is eliminated.
The present invention includes a cannula or delivery apparatus for creating one or more bypasses on-demand between an unobstructed blood vessel such as an aorta and an obstructed vessel such as an obstructed coronary artery. The present invention uses a previously excised vascular segment, such as a saphenous vein or internal mammary artery, or an artificial graft as a conduit. The delivery apparatus delivers various components to the desired location in the interior of the target blood vessel and allows for the deployment of the components remote from the distal end portion of the delivery apparatus. An external assembly is also described to attach an end portion of the conduit to the target vessel and then the external assembly, except for a stent-like member and the conduit, are then removed through the target blood vessel.
The present invention also relates to a device and method for performing an anastomosis from the interior of the target vessel. With this invention, the surgeon may perform either the distal anastomosis or proximal anastomosis first and the surgeon has the ability to choose the desired length of the graft during the procedure. Furthermore, it is anticipated that the distal anastomosis and proximal anastomosis may be performed through a common cannula. In one form of the anastomosis device, the anastomosis device and a cannula are passed through the target vessel to the desired wall of the target vessel. A central guide wire is then passed through the wall of the target vessel and a spoon shaped member is positioned securely against the wall of the target vessel. Next, a cutting cap is secured to the central guide wire along the outside of the target vessel. The graft is then positioned over the cutting cap, guide wire and anastomosis site adjacent to the exterior surface of the target vessel. Staples are then released from the spoon shaped member to pass from the interior of the target vessel to the exterior of the target vessel and into the wall of the graft. The staples may then be manually or automatically crimped to securely retain the graft along the wall of the target vessel. The guidewire is then withdrawn to pull the cutting cap through the wall of the target vessel and into the spoon shaped member. Then entire assembly is then withdrawn and the next anastomosis may be performed as desired.
In another embodiment of the present invention, the cannula is placed in a target vessel such as the aorta. The anastomosis device is then passed through the cannula until the distal end portion reaches the desired position along the wall of the target vessel. The central puncture wire is then passed through the interior wall of the target vessel until a portion of the central puncture wire extends beyond the outer surface of the target vessel. In this embodiment, the central puncture wire is pivotally connected to a cap engaging member that encloses the desired puncture area for the anastomosis device so that the movement of the central guide wire may be coordinated from the exterior of the target vessel along the proximal portion of the anastomosis device. Next, the cutting member of an external assembly is threaded onto the central puncture member. The graft is then attached to the exterior of a proximal portion of a stent-like member and the stent-like member is attached to the cutting member. The external assembly is then drawn towards the cap member so the cutting member pierces the wall of the target vessel. This motion also draws the distal end portion of the stent-like member through the wall of the blood vessel. As with the piercing motion of the central puncture wire, the movement of the external assembly is controlled by movement of a control member located externally of the target vessel along the proximal portion of the anastomosis device. Once the distal end portion of the stent-like member is positioned in a desired location in the interior of the target vessel, the cutting member may be released from the graft and stent-like member of the external assembly to cause the distal end portion of the stent-like member to expand and contact the inner wall of the target vessel. In this position, the distal end portion of the stent-like member is expanded to be positioned adjacent to the inner wall of the target vessel and the middle portion of the stent-like member extends through the wall of the target vessel such that the tissue adjacent to the puncture in the wall of the target vessel contracts against the middle portion of the stent-like member. The distal end portion of the graft surrounds the proximal end portion of the stent-like member. In this embodiment, the seal between the graft and the target vessel is ensured by the seal between the stent-like member and the inner surface of the graft as well as the distal end portion of the stent-like member which causes the end portion of the graft to be drawn against the outer surface of the target vessel.